So after the numbness in my finger tips subsided I carefully collected some, and took a look at the underside of a leaf. Here you can see a nice example of a stinging trichome along one of the leaf veins. The tapered tube is very stiff and brittle due to a composition that includes silicates. The small ball-shaped tip breaks off easily on contact resulting in an extremely sharp point. The bulbous base, although appearing somewhat solid, is actually quite flexible, somewhat like an inflated bag, so that the enclosed liquid (containing sodium formamide, acetyl choline, histamine) is readily "pumped" into the unfortunate creature that pushed against the tube.

Stunning image. As Rik says, it has aesthetic beauty, while conveying scientific information in a very striking way. I love the lighting, it just compliments the image so well._________________Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear

Beautiful! I've been meaning to try these but never got round to it, not sure I'll bother now!! The little ball is very interesting, I suppose if that wasn't there the sharp end would gradually 'erode'...

That's just spectacular. Its as though you have a SEM on your desk instead of a BHA....and the backlighting is amazing, especially coming up through the vein on the leaf. Now I want to thin section a nettle leaf through the trichome.

This was the second leaf tried on the microscope. For the first one I had simply cut out a section and placed it on the slide to photograph. But it was not successful... I watched one trichome after another simply "fall over" as the liquid at the base of the "needle" drained into the cut the leaf section. The rigid needle remained intact, but the base shrunk quickly like a thick balloon with a leak. It illustrated clearly just how flexible the bulbous base is. On the second try I made a tiny "pool" of water (with putty) on the slide, used a whole leaf, and positioned the leaf stem so that it rested in the water. Worked fine.

Last time I posted a shot of this subject (4 years ago!), Betty mentioned its use in salads, as well as nettle eating contests.

I knew that it was used as a salad, but every time I encounter this plant I wonder about the first person to entertain the idea of this as a foodstuff. As I said 4 years ago:

... makes me smile and wonder at the thought process involved in the first person to try that... something like this:
OUCH! This plant is nasty! It really stings and itches if you touch it.... how about we serve some up with dinner?_________________http://www.krebsmicro.com

Wow, that is spectacular. It was one of the things on my to do list. Guess I can skip that one. I think it is not easy to find something that has not been seen on the forum. Not that we have to, but it is fun to discover new subjects.